Neil deGrasse Tyson explains radioactive decay. He explains how we can determine the age of a rock using meteorites and illustrates that atoms undergo nuclear transmutations over time until they become stable elements.

Per Thomas Edison's suggestion, The Secret Labbers visit Frederick Soddy to better understand radioactive decay. Watch Thomas Edison's Secret Lab on Netflix, the Kid Genius channel on Xfinity, public television and DVD. Visit EDISONSECRETLAB.COM for games, videos, downloads and more!

Charlie explains radiocarbon dating and how it is used to calculate the approximate age of an object. To make his explanation more concrete, he uses an analogy involving a refrigerator and the number of ice cubes in it.

Bill Nye explains what volcanoes are, how they're formed, and what causes an eruption. He then explains the impact of volcanoes on the earth's geography.

Scrat places a nut on the ground, causing the Earth to split in half. He travels down the layers of the Earth and chases the nut on the Earth's core. This clip comically shows how the different continents and many of Earth's iconic structures formed.